The present invention relates to a negative film inspection apparatus used together with a photographic printer in which films are exposed based on a large area transmittance density (LATD).
In a large scale photographic printing system, first an LATD is obtained by color, and then exposure is controlled based on the LATD to provide a desirable print condition. Such an LATD printing system has the advantage of providing a print having a favorable density distribution over the print when the print is made from a negative having no difference in density between a principle subject image, such as a human face, and the whole image of the negative.
Because of variations of customers' negatives, it is difficult to make prints with favorable density and color balances from almost all of the customers' negatives by the LATD printing system. As an example, in making a print from a negative including a human figure in a bright background or a human figure in a dark background (a condition generally referred to as having a density failure), or from a negative including an area having a bright color (any one of, or any combination of, red, green, blue, cyan, magenta and yellow) that is too large relative to a principle subject image, such as a human figure (a condition generally referred to as having a color failure), a principal subject image of the negative is underexposed, or with adverse effect from a color of the major part thereof, resulting in a print imbalanced in color and/or density.
To avoid such adverse effect caused by subject failures (density failure and color failure) in the LATD printing system, it has been preferred to inspect negatives prior to making prints from the negatives so as to provide proper exposures for the frames of each negative. In recent years, an improved LATD printing system in which exposure is effected with high accuracy has been developed and has become increasingly popular. The improved LATD printing system measures an original negative to detect three color densities at a large number of points of the original negative and statistically classifies the image pattern of the original negative based on the distribution of the densities. The developed LATD printing system effects an exposure obtained based on the image pattern, a characteristic value of a specific point or area and an LATD of the original negative.
However, because the conventional LATD printing systems are not equipped with an automatic exposure correcting feature for avoiding occurrences of subject failures, it is necessary to provide exposure correction data by inspecting a negative prior to making prints therefrom. Negative inspection generally is effected visually by an operator, and exposure correction value data is recorded manually in a paper tape, for example, using a so-called notcher-puncher. Such a negative inspection not only requires skill but also is quite inefficient. Accordingly, it is difficult for beginners to effect negative inspection with high accuracy and high efficiency.